1. Field of Invention
This invention relates to an oximeter probe which is attached to a part of an object such as a fingertip and in which light emitted from a light emitting portion and passed through living tissue of the object is received by a light receiving portion, so that the pulse wave of blood flowing through a blood vessel is detected and the oxygen saturation of blood is measured.
2. Related Art
In such an oximeter probe, conventionally, an LED functioning as the light emitting portion, and a photodetector (hereinafter, as "PD" when applicable) functioning as the light receiving portion are mounted on a flexible printed circuit board (hereinafter, as "FP board" when applicable), the FP board is wound on a fingertip, and a light shielding tape is wound on the outer periphery. Under this state, the oxygen saturation is measured.
In the prior art oximeter probe, optical noises such as external light are prevented from entering the PD by winding the FP board with the light shielding tape, but no countermeasure against electrical noises is taken. Accordingly, there arises a problem in that electrical noises from the outside enter the FP board, particularly the PD to produce an error in measuring results.